I am one of those people for whom genealogy searches would be next to impossible. I have very little information on my mothers side and even less on my father's side. No place to even start the search, my Gma's "maiden" name she told us I do not think is her actual maiden name, but the people who raised her, but not officially adopted or even legally guardians. Her birth mother was always referred to as "the woman" she never said either her first or last name to my father or me. Her mother had 10 children by 9 different men (a set of twins) my gma only met 3 of them (the half siblings as children) she either didn't know or wouldn't say who my gma's father was. Anyway the likelihood of me finding anything is slim to none.
That being said I have had several friends do the Ancestry dna test and I have seen their results and it is pretty vague. So while I don't buy into the whole "sky is falling" idea of the "dangers" of the test until they get a lot more specific and a lot more detailed I'll keep my $100 and spend it on fabric and maybe some wine.